Woven fabric structure

ABSTRACT

The present invention relates to a woven fabric structure including at least one array of warp yarns interwoven with at east one array of substantially orthogonally extending weft yarns, wherein each end of a warp yarn is extended beyond the last weft to form either a binder or a seam loop which can be interdigitated with similar seam loops of the opposing fabric end and joined by at least one pintle wire passed through a tunnel formed by the interdigitated seam loops. The inventive woven fabric structure is characterized in that the seam loops and the binders of the warp yarns possess a ratio above 1:1 and below 4:1.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a woven fabric structure including at least one array of warp yarns interwoven with at least one array of substantially orthogonally extending weft yarns, wherein each end of a warp yarn is extended beyond the last weft yarn to form either a binder or a seam loop which can be interdigitated with similar seam loops of the opposing fabric end and joined by at least one pintle wire passed through a tunnel formed by the interdigitated seam loops.

2. Description of the Related Art

The woven fabric is for papermachine clothing, such as a forming fabric, a press sleeve, an extended nip press belt, a dryer fabric, a base cloth, for a filter belt or for a conveyor belt.

A common form of seam is achieved by extending selected longitudinal (machine direction) warp yarns of the fabric beyond the last transverse (cross-machine direction) weft yarn to form a loop, the end of which is back-woven into the fabric. The non-selected machine direction warp yarns are looped about the last cross-direction weft yarn the end of which is woven and the end back-woven into the fabric. Such a fabric structure is described in the British Patent Application GB-A-1,488,815, which discloses two patterns of weaving back the looped yarns and cutting short of certain other machine direction yarns to provide space for the back woven loop ends.

All warp yarns usually have the same thickness or width, so that as a result when using only half the warp yarns to form the loops, to afford space for interdigitation of the corresponding loops of the opposite end of the fabric, the tensile strength of the seam is significantly less than the fabric strength and there is a higher propensity in the seam region for marking the material sheet due to the greater open area in the seam region, as about 50% of the total width of the fabric is open space.

One approach of solving this problem is to use more than 50% of the warp yarns to form loops. An example of this is the International Patent Application WO 92/15743 A1 wherein the problem of obtaining space for interdigitation of loops where more than 50% space is used by the loops of each side is tackled by crossing adjacent loops over each other. However, the use of more than 50% warp yarns and the crossing of the looped yarns make the already complicated, prolonged, and expensive seaming process even more protracted.

Finally, the European Patent Specification EP 1 070 164 B1 discloses a woven fabric structure including an array of warp yarns interwoven with an array of substantially orthogonally extending weft yarns using warp yarns of differing widths. The warp yarns include groups of relatively wide warp yarns and groups of relatively thin warp yarns, said groups of relatively wide warp yarns alternating with said groups of relatively thin warp yarns. The groups of relatively wide and relatively thin warp yarns each include two or more respectively wide or thin warp yarns and said relatively wide warp yarns are extended in a seam region to provide seaming loops on each end of the fabric. The disadvantage of this woven fabric structure is that warp yarns of different size can produce an uneven fabric surface leading to marking of the material sheet.

What is needed in the art is a woven fabric structure with an improved tensile strength, less open space and a reduced propensity in the seam region for marking the material sheet.

SUMMARY OF THE INVENTION

The present invention provides that the seam loops and the binders of the warp yarns possess a ratio above 1:1 and below 4:1.

This ratio provides a woven fabric structure with an improved tensile strength, a lower open space, and a reduced propensity in the seam region for marking the material sheet.

The ratio of the seam loops to the binders is 3:1, 2:1, or 3:2. The ratio of “3:1” means three seam loops, one binder, three seam loops, one binder, three seam loops, etc. The ratio of “2:1” means two seam loops, one binder, two seam loops, one binder, two seam loops, etc. The ratio of “3:2” means either two seam loops, one binder, one seam loop, one binder, two seam loops, one binder, one seam loop, one binder, two seam loops, etc. or three seam loops, two binders, three seam loops, two binders, three seam loops, etc. These three ratios provide highly improved tensile strengths with significant lower open spaces. The propensity in the seam region for marking the material sheet is consequently reduced.

According to two embodiments of the present invention, the warp yarns for the seam loops are flat or profiled yarns with overall dimensions between 0.25 and 1.00 mm in height and between 0.50 and 2.00 mm in width, or they are round yarns with a diameter between 0.25 and 1.00 mm. Furthermore, the warp yarns are of a circular, rectangular, or other profile shaped cross-section. The other profile shaped cross-section will have the shape of a triangle, semicircle, hexagon, octagon, or parallelogram.

Moreover, according to an embodiment of the present invention the warp yarn has a cross-sectional area between 0.125 and 2.00 mm² for the flat or profiled yarns and between 0.05 and 0.79 mm² for the round yarns. These ranges guarantee a reduced propensity of the woven fabric structure and, therefore, a reduced marking of the material sheet. The material sheet is a paper, board, or tissue sheet.

In order to significantly reduce marking of the material sheet, the warp yarns and the weft yarns have the same, similar, or different shapes and cross-sectional areas.

The present invention further provides papermachine clothing formed by seaming a woven fabric structure according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIGS. 1-3 are three fragmentary, enlarged, detail views of parts of seam regions of woven fabrics, showing parts of the weave structures of the fabrics of the seam formations;

FIG. 4 is a fragmentary, enlarged, detail view of part of a seam region of a woven fabric, showing part of the weave structure of the fabric of the seam formation; and

FIGS. 5-7 are three fragmentary, enlarged, detail views of parts of seam regions of woven fabrics according to the invention, showing parts of the weave structures of the fabrics of the seam formations.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIGS. 1-4, there is shown a woven fabric structure for a papermachine clothing or another belt, such as a filter or conveyor belt, including an array of cross-machine direction weft yarns 10, extending parallel to an edge of the fabric 1, and a last weft yarn 10 a, defining the edge. An array of warp yarns 12 is woven through the weft yarns 10 substantially orthogonally to the weft yarns 10 of, and in machine direction of, the fabric 1.

It is shown in the embodiment of FIG. 1, which shows a fragmentary, enlarged, detail view of part of a seam region of a woven fabric 1, that a normal loop seam is made by reweaving the first machine direction warp yarn 12.1 back into the fabric 1 to form a loop 14. The second machine direction warp yarn (12.2 is not visible) is brought out of the fabric within the seam area. This leaves a space for the first machine direction warp yarn to replace the pathway of the second machine direction warp yarn. The third machine direction warp yarn 12.3 is then rewoven back into the fabric to form a binder by replacing the path of the fourth machine direction warp yarn 12.4. The process is repeated so that 50% of the seam includes loops 14 and 50% of the seam includes binders 16.

The seam loops 14 and the binders 16 are interdigitated with similar seam loops 14 of the opposing fabric end and joined by a pintle wire 18 passed through a tunnel 20 formed by the interdigitated seam loops 14.

Another possibility to join two fabric ends together is the use of a spiral connecting the seam loops of the two opposing fabric ends. A spiral is used in connecting the seam loops of the two opposing fabric ends of a dryer fabric.

Furthermore, according to the embodiment of FIG. 2, some designs of fabrics 1 have two layers A, B of thin machine direction warp yarns 22. The seam loops 24 are made by reweaving one machine direction warp yarn 22.1 of the first layer A back into the fabric 1 to form a seam loop 24 by replacing the path of the second machine direction warp yarn 22.2 of the second layer B. The third machine direction warp yarn 22.3 is then rewoven back into the fabric 1 of the first layer A to form a binder 26 by replacing the path of the fourth machine direction warp yarn 22.4 of the second layer B. The process is repeated so that 50% of the seam is includes seam loops 24 and 50% of the seam includes binders 26. A fabric 1 of this design is disclosed in the European Patent Specification EP 0 612 881 B1.

As shown in FIG. 3, it is also possible to increase the number of seam loops 34 by making a seam without binders 36 so that 50% of the seam forms seam loops 34 around a pintle wire 38 a. Then 50% of the seam forms seam loops 34 around a second pintle wire 38 b.

FIG. 4 shows another fragmentary, enlarged, detail view of part of a seam region of a woven fabric 1, showing part of the weave structure of the fabric 1 of the seam formation. The seam loops 44 and the binders 46 of the warp yarns 42 possess a ratio R of 1:1, e.g. one seam loop 44, one binder 46, one seam loop 44, one binder 46, one seam loop 44, etc. Additionally, the warp yarns 42 for the seam loops 44 are either flat or profiled yarns with overall dimensions between 0.25 and 1.00 mm in height and between 0.50 and 2.00 mm in width, or they are round yarns with a diameter between 0.25 and 1.00 mm. A practical embodiment will have over 48 seam loops 44 with a width of 100 mm and 11.52 mm² cross-sectional area F in total.

Additional fragmentary, enlarged, detail views of parts of seam regions of woven fabrics 1 are shown in FIGS. 5, 6 and 7. Each fabric 1 includes an array of cross-machine direction weft yarns 100, extending parallel to an edge of the fabric 1, and includes a last weft yarn 100 a, defining the edge. An array of warp yarns 102 is woven through the weft yarns 100 substantially orthogonally to the weft yarns 100 of and in machine direction of the fabric 1.

Each end of a warp yarn 102 is extended beyond the last weft yarn 100 a to form either a binder 106 or a seam loop 104 which can be interdigitated with similar seam loops 104 of the opposing fabric end and joined by a pintle wire 108 passed through a tunnel 110 formed by the interdigitated seam loops 104.

The seam loops 104 and the binders 106 of the warp yarns 102 possess a ratio R above 1:1 and below 4:1. For example, the ratio R can be 2:1 as shown in FIG. 5 or 3:2 as shown in FIGS. 6 and 7. According to the first ratio R, the warp yarns 102 have two seam loops 104, one binder 106, two seam loops 104, one binder 106, two seam loops 104, etc. According to the second ratio R, the warp yarns 102 have three seam loops 104, two binders 106, three seam loops 104, two binders 106, three seam loops 104, etc. or two seam loops 104, one binder 106, one seam loop 104, one binder 106, two seam loops 104, etc. These two ratios provide highly improved tensile strengths with significant lower open spaces. The propensity in the seam region for marking the material sheet is consequently reduced.

Additionally, the warp yarns 102 for the seam loops 104 are either flat or profiled yarns with overall dimensions between 0.25 and 1.00 mm in height and between 0.50 and 2.00 mm in width or are round yarns with a diameter between 0.25 and 1.00 mm. The warp yarns 102 of both embodiments are of a circular, rectangular or other profile shaped cross-section C and have a cross-sectional area F between 0.125 and 2.00 mm² for the flat or profiled yarns and between 0.05 and 0.79 mm² for the round yarns. A practical embodiment with a ratio of 2:1 will have over 64 seam loops 104 with a width of 100 mm and 15.36 mm² cross-sectional area F in total (0.36 mm in height and 0.67 mm in width). This is a 33% increase in material around the seam pintle with respect to the embodiment of FIG. 4.

Moreover, the warp yarns 102 and the weft yarns 104 have the same, similar, or different shapes S and cross-sectional areas F.

The woven fabric 1 can be used for papermachine clothing, such as a forming fabric, a press sleeve, an extended nip press belt, a dryer fabric, a base cloth, for a filter belt or for a conveyor belt.

While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

REFERENCE NUMERALS LIST

-   -   1 fabric     -   10 weft yarn     -   10 a last weft yarn     -   12 warp yarn     -   12.1 warp yarn     -   12.2 warp yarn     -   12.3 warp yarn     -   12.4 warp yarn     -   14 seam loop     -   16 binder     -   18 pintle wire     -   20 tunnel     -   22 warp yarn     -   22.1 warp yarn     -   22.2 warp yarn     -   22.3 warp yarn     -   22.4 warp yarn     -   24 seam loop     -   26 binder     -   34 seam loop     -   36 binder     -   38 a pintle wire     -   38 b pinte wire     -   42 warp yarn     -   44 seam loop     -   46 binder     -   100 weft yarn     -   100 a last weft yarn     -   102 warp yarn     -   104 seam loop     -   106 binder     -   108 pintle wire     -   110 tunnel     -   A first layer     -   B second layer     -   C cross-section     -   F cross-sectional area     -   R ratio     -   S shape 

1. A woven fabric structure comprising: at least one array of a plurality of weft yarns; and at least one array of a plurality of warp yarns interwoven with and extending substantially orthogonally to said at least one array of said plurality of weft yarns, said plurality of warp yarns including at least one binder and a first plurality of seam loops, each of said plurality of warp yarns having at least one end extending beyond a last said weft yarn, said at least one end comprising one of said binder and said seam loop, each said binder and each said seam loop being configured for interdigitating with a similar second plurality of seam loops of an opposing fabric end and for joining by at least one pintle wire passed through a tunnel defined by interdigitated said first and second pluralities of seam loops, said first plurality of seam loops and said at least one binder defining a ratio of said first plurality of seam loops to said at least one binder, said ratio being above 1:1 and below 4:1.
 2. The woven fabric structure according to claim 1, wherein said ratio is one of 3:1, 2:1, and 3:2.
 3. The woven fabric structure according to claim 1, wherein each of said plurality of warp yarns for said first plurality of seam loops is one of a flat and a profiled yarn with overall dimensions between 0.25 and 1.0 mm in height and between 0.5 and 2.0 mm in width.
 4. The woven fabric structure according to claim 3, wherein each of said plurality of warp yarns comprises one of a rectangular-shaped cross-section and a profile-shaped cross-section.
 5. The woven fabric structure according to claim 3, wherein each of said plurality of warp yarns has a cross-sectional area between 0.125 and 2.0 mm².
 6. The woven fabric structure according to claim 3, wherein each of said plurality of warp yarns and each of said plurality of weft yarns has one of a same, a similar, and a different shape relative to one another and one of a same, a similar, and a different cross-sectional area relative to one another.
 7. The woven fabric structure according to claim 1, wherein each of said plurality of warp yarns for said first plurality of seam loops is a round yarn with a diameter between 0.25 and 1.0 mm.
 8. The woven fabric structure according to claim 7, wherein each of said plurality of warp yarns comprises a circular-shaped cross-section.
 9. The woven fabric structure according to claim 7, wherein each of said plurality of warp yarns has a cross-sectional area between 0.05 and 0.79 mm² for said round yarns.
 10. A papermachine clothing comprising: a first and second woven fabric each comprising: at least one array of a plurality of weft yarns; at least one array of a plurality of warp yarns interwoven with and extending substantially orthogonally to said at least one array of said plurality of weft yarns, said plurality of warp yarns including at least one binder and a first plurality of seam loops, each of said plurality of warp yarns having at least one end extending beyond a last said weft yarn, said at least one end comprising one of said binder and said seam loop, each said binder and each said seam loop being configured for interdigitating with a similar second plurality of seam loops of an opposing fabric end and for joining by at least one pintle wire passed through a tunnel defined by interdigitated said first and second pluralities of seam loops, said first plurality of seam loops and said at least one binder defining a ratio of said first plurality of seam loops to said at least one binder, said ratio being above 1:1 and below 4:1; and wherein said first and said second woven fabrics include a seam therebetween, said seam comprising an interdigitation of at least one of said binder and said seam loop of said first and second woven fabrics and a pintle wire through a tunnel defined by interdigitated said pluralities of seam loops of said first and second woven fabrics. 